Bio Chapter 14

start codon + official name

AUG, methionine

stop codons

UAA, UAG, UGA

mRNA

a working copy of the portion of DNA that will be used to make a protein, after being made in the nucleus, it travels to the cytoplasm, the site of protein synthesis

rRNA

happens in translation, subunits of ribosomes are made up of several molecules of this, which reads mRNA, calls over tRNA, and helps in building polypeptide bond

central dogma of biology

DNA → mRNA → protein

tRNA

carries amino acids from the cytoplasm to the mRNA, dropping off the amino acids to build up a polypeptide, or straight chain of amino acids

Promoters

RNA polymerase binds to DNA at these regions

mRNA editing

introns are taken out, exons are expressed and turned into protein

Transcription step-by-step

1. DNA molecule is unzipped by RNA polymerase

2. RNA polymerase reads template strand of DNA at promoter sequence

3. RNA polymerase adds on complementary RNA bases (uracil instead of thymine)

4. Sequence is edited, introns taken out, exons expressed

Translation step-by-step

1. edited mRNA leaves nucleus and goes to a ribosome

2. mRNA is read by the ribosome in three letter codons

3. rRNA in ribosome calls over tRNA which brings the anticodon and corresponding amino acid

4. the ribosome helps to build peptide bond to producing growing polypeptide chain (amino acid chain)

5. this process stops when stop codon is read

codon

three nucleotide bases in mRNA that specifies a particular amino acid

how many common amino acids?

20

anticodon

holds the complementary base pair to the codons of mRNA

RNA

a molecule which helps organisms in protein synthesis/create proteins single-stranded nucleic acid that contains the sugar ribose

RNA polymerase

enzyme that links together the growing chain of RNA strands during transcription using a DNA strand as a template

intron

sequence of DNA that is not involved in coding for a protein and is removed from mRNA

exon

expressed sequence of DNA; codes for a protein

transcription

synthesis of an RNA molecule from a DNA template

operon

a group of genes that are regulated together

differentiation

a process in which cells become specialized in structure and function

differences: RNA

• single stranded

• contains uracil

• ribose is sugar

• 3 types

  • mRNA, rRNA, tRNA

differences: DNA

• double stranded

• contains thymine

• deoxyribose is sugar

similarities between RNA and DNA

• contains bases cytosine, guanine, and adenine

• 4 bases

• both nucleic acids

• contains genetic information

frameshift mutation

a type of mutation that inserts of deletes bases and shifts the “reading frame” (insertion or deletion)

point mutation

type of mutation that only changes a single base by substituting one for another

silent mutation

mutation that does not result in a change in the amino acid sequence

mutation

any change in the DNA sequence

mutagen

chemical or physical factors in the environment that interact with DNA and may cause a mutation

polyploidy

condition in which an organism has extra sets of chromosomes

duplication

extra copies of genes are generated in the chromosome

deletion

some of the genetic material in the chromosome breaks off

inversion

a chromosome segment gets reversed

translocation

a part of one chromosome breaks off and attaches to another